The game is perfect for ages 8 and up
Research recent sales data and current market values, assess the condition of your cards, and consider their rarity and demand
Its also probably the easiest to upgrade as both ink colors have good reasonably-priced options or very expensive but excellent ones
Arna Kennerd, Skycaptain is one such legend, bringing back the 'modified' keyword from Kamigawa: Neon Dynasty in an interesting new color combination: Esper (or white-blue-black)
Good trap cards are those that can: prevent attacks like Mirror Force, negate summons like Solemn Warning, negate spell/trap activations like Wiretap, negate effects like Breakthrough Skill or Fiendish Chain, remove monsters like Ring of Destruction or Compulsory Evacuation Device, and prevent your opponent from making plays like Vanity's Emptiness
Bandit Citadel Plane: Kamigawa Whenever a creature attacks, it gets +2/+0 until end of turn